[time-nuts] quartz crystal configuration in small cases

ALAN MELIA alan.melia at btinternet.com
Tue Mar 13 21:40:00 UTC 2012


Hi Bob thanks for that. In replying to Atilla's query I did hope to trigger some responses that would update my knowedge as well. My experience of resonators is some 40 years old. Do you know if the older more massive blanks have a higher "Q" than these small bar ATs. All the high quality resonators I have come across have been relatively massive.

Alan

--- On Tue, 13/3/12, Bob Camp <lists at rtty.us> wrote:

> From: Bob Camp <lists at rtty.us>
> Subject: Re: [time-nuts] quartz crystal configuration in small cases
> To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
> Date: Tuesday, 13 March, 2012, 21:10
> Hi
> 
> The typical AT low cost crystal is an AT strip. It's
> rectangular rather than
> circular. It still resonates across the thickness dimension,
> just as the
> circular part does. 
> 
> A modern 32 KHz crystal is set up as a tuning fork. 
> The resonance happens
> each "arm" along it's length. Long ago 32 KHz crystals were
> made as strips
> that resonated along the length of the strip. A part that
> resonates along
> it's length is often called a bar in the literature.
> 
> Bob
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com]
> On
> Behalf Of ALAN MELIA
> Sent: Tuesday, March 13, 2012 4:47 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] quartz crystal configuration in
> small cases
> 
> hi Magnus the only "bar" resonators I have actually seen
> were NT flexural
> bar. Modern cuts probably include all sorts of resonator
> modes....but are
> these AT cuts?
> 
> Alan
> 
> --- On Tue, 13/3/12, Magnus Danielson <magnus at rubidium.dyndns.org>
> wrote:
> 
> > From: Magnus Danielson <magnus at rubidium.dyndns.org>
> > Subject: Re: [time-nuts] quartz crystal configuration
> in small cases
> > To: time-nuts at febo.com
> > Date: Tuesday, 13 March, 2012, 17:59
> > On 03/13/2012 06:35 PM, ALAN MELIA
> > wrote:
> > > Hi Atilla, I dont have book availabe but AT cut is
> a
> > thickness-shear vibration mode so plate area may not be
> an
> > issue ?? Just harder to make :-))
> > 
> > One of the AT cut oscillators I use has a crystal bar
> rather
> > than a circular plate. Being mass-produced in bulk,
> etched
> > etc. It is just a different process.
> > 
> > I'm sure the crystal oscillator folks here could point
> to
> > some good sources on that.
> > 
> > Cheers,
> > Magnus
> > 
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